apache/iceberg · error · UnsupportedOperationException

Not a supported type:

Error message

Not a supported type: 

What it means

SparkValueConverter.convert maps Iceberg primitive types to Spark-compatible values and throws UnsupportedOperationException for any type it does not explicitly handle. It is a deliberate capability guard: the converter only supports a fixed set of primitive types (the visible cases pass through DOUBLE/DECIMAL/STRING/FIXED values unchanged), so encountering an unhandled typeId means the requested conversion is outside the converter's supported surface.

Source

Thrown at spark/v4.1/spark/src/main/java/org/apache/iceberg/spark/SparkValueConverter.java:90

        // if spark.sql.datetime.java8API.enabled is set to true, java.time.LocalDate
        // for Spark SQL DATE type otherwise java.sql.Date is returned.
        return DateTimeUtils.anyToDays(object);
      case TIMESTAMP:
        return DateTimeUtils.anyToMicros(object);
      case BINARY:
        return ByteBuffer.wrap((byte[]) object);
      case INTEGER:
        return ((Number) object).intValue();
      case BOOLEAN:
      case LONG:
      case FLOAT:
      case DOUBLE:
      case DECIMAL:
      case STRING:
      case FIXED:
        return object;
      default:
        throw new UnsupportedOperationException("Not a supported type: " + type);
    }
  }

  private static Record convert(Types.StructType struct, Row row) {
    if (row == null) {
      return null;
    }

    Record record = GenericRecord.create(struct);
    List<Types.NestedField> fields = struct.fields();
    for (int i = 0; i < fields.size(); i += 1) {
      Types.NestedField field = fields.get(i);

      Type fieldType = field.type();

      switch (fieldType.typeId()) {
        case STRUCT:
          record.set(i, convert(fieldType.asStructType(), row.getStruct(i)));

View on GitHub (pinned to 86d9c8fc54)

Solutions

1. Check the Iceberg type of the offending column and confirm the converter version handles it; upgrade to an Iceberg/Spark version where the type is supported
2. Convert unsupported types (e.g. timestamps, binary) manually before calling the converter
3. If the type should be supported, upgrade the iceberg-spark module or file an issue to extend the switch

Example fix

// before
Object sparkVal = SparkValueConverter.convert(structType, row); // throws for TIMESTAMP field
// after
Object raw = row.get(tsFieldPos);
Object sparkVal = raw instanceof Long
    ? DateTimeUtils.microsToTimestamp((Long) raw)
    : SparkValueConverter.convert(structType, row);

Set<Type.TypeID> supported = Set.of(Type.TypeID.BOOLEAN, Type.TypeID.INTEGER, Type.TypeID.LONG,
    Type.TypeID.FLOAT, Type.TypeID.DOUBLE, Type.TypeID.DECIMAL, Type.TypeID.STRING, Type.TypeID.FIXED);
if (!supported.contains(type.typeId())) {
  throw new IllegalArgumentException("Column type not supported by converter: " + type);
}

boolean isSupportedPrimitive(Type t) {
  switch (t.typeId()) {
    case BOOLEAN: case INTEGER: case LONG: case FLOAT: case DOUBLE:
    case DECIMAL: case STRING: case FIXED:
      return true;
    default:
      return false;
  }
}

try {
  value = SparkValueConverter.convert(structType, row);
} catch (UnsupportedOperationException e) {
  LOG.warn("Unsupported type conversion, passing raw value through", e);
  value = row.getField(fieldName);
}

When it happens

Trigger: Calling the public convert method with an Iceberg type whose typeId falls into the switch's default branch - e.g. a TIMESTAMP, TIMESTAMP_NS, DATE, UUID, or BINARY column passed through this conversion path.

Common situations: Reading or writing tables containing timestamp, binary, or uuid columns via Spark code paths that use SparkValueConverter for row conversion; using newer Iceberg type kinds (timestamp-nanoseconds) with an older Spark integration module.

Understand the failure class

Background: UnsupportedOperationException and "is not supported" errors: when a library deliberately refuses a call — this error's family across 30 libraries.

Related errors

• Unsupported YearMonthIntervalType.
• Unsupported DayTimeIntervalType.
• Unsupported DistinctType.
• Unsupported StructuredType.
• Unsupported type: %s

AI-assisted analysis of apache/iceberg@86d9c8fc54 (2026-09-12). Data as JSON: /api/errors/ae0347d029348433. Report an issue: GitHub.